scsi: libsas: fix error when getting phy events

The intend purpose here was to goto out if smp_execute_task() returned
error. Obviously something got screwed up. We will never get these link
error statistics below:

~:/sys/class/sas_phy/phy-1:0:12 # cat invalid_dword_count
0
~:/sys/class/sas_phy/phy-1:0:12 # cat running_disparity_error_count
0
~:/sys/class/sas_phy/phy-1:0:12 # cat loss_of_dword_sync_count
0
~:/sys/class/sas_phy/phy-1:0:12 # cat phy_reset_problem_count
0

Obviously we should goto error handler if smp_execute_task() returns
non-zero.

Fixes: 2908d778 ("[SCSI] aic94xx: new driver")
Signed-off-by: NJason Yan <yanaijie@huawei.com>
CC: John Garry <john.garry@huawei.com>
CC: chenqilin <chenqilin2@huawei.com>
CC: chenxiang <chenxiang66@hisilicon.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/libsas/sas_expander.c

@@ -686,7 +686,7 @@ int sas_smp_get_phy_events(struct sas_phy *phy)
 	res = smp_execute_task(dev, req, RPEL_REQ_SIZE,
 			            resp, RPEL_RESP_SIZE);
 
-	if (!res)
+	if (res)
 		goto out;
 
 	phy->invalid_dword_count = scsi_to_u32(&resp[12]);